# Water Waves and Tuning fork

1. Jan 28, 2009

### ahrog

1. The problem statement, all variables and given/known data
1. Water waves in a lake travel 4.4m in 1.8s. The period of oscillation is 1.2 s.
a) What is the speed of the water waves?
b) What is the period of the water waves?
2. A group of swimmers is resting in the sun on an off-shore raft. They estimate that 2.0m separates a trough and an adjacent crest of the surface waves on the lake. They count 14 crests that pass by the raft in 20s. How fast are the waves moving?
3. a) A tuning fork vibrates 192 times in 1.50 s. What is its frequency?
b) What is it's period?

2. Relevant equations

v=wavelength x frequency
frequency=1/ T

3. The attempt at a solution
1. a) v=d/t
4.4m/1.8s
=2.4m/s

b) f=1/T
=1/1.2s
=0.83 Hz

2.) v= wf
=(6m)(14 crests/20s)
=4.2m/s

3. a) f=1/T =1/(1.5s/192) = 128Hz
b) T=192vibrations/1.50 seconds
=0.00781 s

I just need someone to check these over, as they are worth a portion of my grade, and I don't want to make stupid mistakes.

2. Jan 28, 2009

Question 1b